Hydrogen adsorption and desorption on the Pt and Pd subnano clusters — a review

In this review, we present our recent first principles studies on the sequential H2 dissociative chemisorption and H desorption on the Ptn and Pdn clusters (n=2–9, 13). Upon full saturation by H atoms, the calculated H2 dissociative chemisorption energy and H desorption energy on Pt13 and Pd13 clusters are similar to the corresponding values on smaller close-packed clusters. Indeed, the catalytic performances of these subnano clusters do not vary significantly with the particle sizes or shapes. Instead, they are dependent on the surface metal atoms which can be accessed by H atoms. In addition to the coverage dependency of the H2 dissociative chemisorption and H sequential desorption energies, the phase transition of both Pt13 and Pd13 from the icosahedral to fcc-like structures at certain H coverage was also investigated.